Multi-photon fluorescence scanning microscopy is a powerful new tool for cellular visualization that has several significant advantages over other existing imaging technologies. Like confocal microscopy, multi- photon microscopy has optical sectioning capabilities that exclude out- of-focus information from the final image. However, by virtue of a non- linear multi-photon effect, fluorescence excitation is restricted to a diffraction-limited spot that can be raster scanned across the sample, resulting in an image with inherent confocal properties. In addition, this effect is generated using lower energy near-infrared light, which is far less damaging to living cells and deeper penetrating than visible and ultraviolet light sources. These fundamental features of a multi-photon microscope make it ideally suited for imaging cellular and subcellular processes in thick and/or living samples. Acquisition of a state-of-the-art multi-photon microscope will have a dramatic impact on the quality and scope of research and educational endeavors at the University of Delaware. Several NIH funded research programs that would immediately benefit from this instrumentation include 1) embryogenesis and implantation, 2) mechanisms of lens fiber cell differentiation, 3) gene therapy using chimeric oligonucleotides, 4) effects of bone matrix proteins on the progression of prostate cancer and voltage-sensitive calcium channel expression in osteoblasts, 5) proteinaceous membranes of the chicken egg, 6) Ca2+ as an intracellular signal in bone and muscle cells, 7) role of calcium and integrin binding protein (CIB) during cellular migration. The University of Delaware fully anticipates that the placement of a much needed multi-photon microscope in our multi-user core bio-imaging facility will provide critical experimental data for our biomedical research programs that is either seriously limited or not possible with any existing equipment on campus.